Inkjet computer-to-plate (CTP) technique is a technique that utilizes an inkjet printing apparatus to spray images directly on printed substrates. At present, the printed substrate is mainly applied with aluminum substrate. In order to improve the durability and resolution of the aluminum substrate, the aluminum plate is usually undergone anodic oxidation and graining treatment to form a certain degree of roughness on its surface (see CN85100875A). In the process of anodic oxidation treatment, the aluminum plate is necessarily pretreated with a large quantity of acid and alkali, while the waste liquid of acid and alkali is not only prone to cause relatively serious environmental pollution, but also increase overall manufacturing cost of the finished substrate. CN1295307A discloses that water-soluble natural polymer and water-soluble synthesized polymer are applied on the image receiving layer, but the aluminum substrate still needs a treatment of anodic oxidation.
The main object of the present invention is to add nano-size and/or micron-size oxide particle into polymer, then apply the obtained coating material on surface of a aluminum plate, so as to form a certain degree of roughness on the surface of the aluminum plate, thereby avoid an anodic oxidation treatment and protect environment.